The first time you run the apk, you can install it directly, but after uninstalling, the AS will fail to run the installation directly. In addition, putting output--->debug.apk into the phone for installation will prompt: invalid installation package, incompatible with the operating system. At first, I thought it was caused by incorrect configuration or settings.
Solution:
Method 1: The package name of adb uninstall project. Then run it again to install.
The following are the reasons found:
First, each Android software has its own signature, but for the convenience of developers, Google provides a debug signature. We usually use this signature when developing and debugging. It is an informal signature.
Second, the system is based on Sign to judge whether an application has been installed.
Third, although the domestic manufacturer’s system is Android (Meizu, Huawei mate10Pro), it has changed a lot. The most pitted part of this strange change is that the signature is still retained after uninstalling the app, so smart Continue to install the debug signature program, the official program is not correct!
In addition: INSTALL_FAILED_VERSION_DOWNGRADE this kind of error
You can try: adb install -t A-debug.apk